EL CONDOR PASA was composed by Daniel Alomía Robles in 1913 (but not registered until 1933), in Quechua AND Spanish, and based on a traditional Quechuan tune. Robles was a Peruvian folklorist and musician who was living in Bolivia at the time and studying Bolivian music. It was composed for a zarzuela by Julio Baudouin y Paz. Recorded by many groups, including the well-known and recorded Argentine Andean music group Los Incas.
Paul Simon heard Los Incas in France, and composed his own (silly) words, using the music of the recording by Los Incas.

Information at these sites:
http://ttibes.tribe.net/m/quechua/thread/2e6f5f3f-6cfe-469c-8ce5-9cb8ca7782a3
This site also has an almost word-by-word interpretation of the Quechua.

El condor pasa
This wikipedia article in Spanish is informative, with the Quechuan lyrics and a Spanish translation, and references.

http://www.philip-jacobs.de/runasimi/y-kuntur.htm
This excellent site not only has the story of the song, but the lyrics in Quechua, Spanish and English, a score for piano, and a score and lyrics after Daniel Alomia Robles.
Kuntur phawan

Note: The language of the Quechua is also known as Runasimipi.